Due to their high temperature capabilities, ceramic matrix composite (CMC) materials are often desirable in components operating under elevated temperatures. CMC materials generally comprise a ceramic fiber reinforcement material embedded in a ceramic matrix material. The reinforcement material may be discontinuous short fibers dispersed in the matrix material, continuous fibers, or fiber bundles oriented within the matrix material, and serves as the load-bearing constituent of the CMC. In turn, the ceramic matrix protects the reinforcement material, maintains the orientation of its fibers, and serves to dissipate loads to the reinforcement material.
Often, the fabrication of CMCs includes using multiple prepreg layers formed by impregnating a desired ceramic fiber reinforcement material with a slurry containing one or more precursors of the CMC matrix material, and organic resin binders. The one or more precursors are selected based upon a desired composition for the ceramic matrix of the CMC component. For example, the precursors for silicon-based composites, such as silicon carbide (SiC), which are of particular interest for high-temperature applications, include SiC powder and/or one or more carbon-containing materials that are ultimately converted to SiC upon reaction with molten Si. However, during the production of the SiC CMC components, some of the molten silicon may not react with other contents of the matrix, resulting in free elemental silicon and/or silicon alloy.
Current methods for determining the amount of free silicon often require destruction of the sample or component being tested. For example, one method includes dissolving the samples in an acid that does not affect silicon. Not only is dissolving the sample costly from both a time and raw material perspective, it also presents some element of danger. Other methods, such as Atom Probe Tomography and Secondary Ion Mass Spectroscopy, also require the sample component be destroyed.
A method and an article with improvements in the process and/or the properties of the components formed would be desirable in the art.